Google and Microsoft want to do the same thing for personal health that software such as Quicken has already done for people’s personal finances. Google Health, which was released in May, and Microsoft HealthVault, which launched last October, allow consumers to store and manage their personal medical data online. Users will be able to gather information from doctors, hospitals, and testing laboratories and share it with new medical providers, making it easier to coördinate care for complicated conditions and spot potential drug interactions or other problems. Both Google and Microsoft will also offer links to third-party services like medication reminders and programs that track users’ blood-­pressure and glucose readings over time.

Patients already have a legal right to copies of their medical data–information that they paid for and own. But in practice, that right is often difficult to exercise: patients must traipse from lab to hospital, waiting in line for photocopies of CT scans, prescription records, and discharge summaries. That’s because many doctors still do not use electronic records, and others are unwilling or unable to transfer data to patients in electronic form. In a 2007 Wall Street Journal Online/Harris Interactive poll, only about a quarter of respondents reported having electronic records, generally in their doctor’s offices; just 2 percent of all respondents said they had created and maintained medical records on their own computers, and just 1 percent reported using a “personal health record that is stored on the Internet.” HealthVault and Google Health just may push doctors and hospitals to adopt electronic records at last.

What Google and Microsoft promise to do with electronic records is also a radical departure, both conceptually and in practice. Those patients who do currently have electronic access generally use portals maintained by doctors or health-care systems. Typically, patients can view information such as prescriptions, lab results, and diagnoses; sometimes they can e-mail doctors or make appointments online. In most cases, though, patients do not control their own data, so they cannot transfer it electronically to a different health-care provider or plug it in to third-party applications.

With HealthVault and Google Health, however, consumers will have fundamental ownership of their medical data, much as they do with financial records. As more health-care providers begin participating, it will be easy for patients to share CT scans, x-rays, and lab results with new doctors. In the emergency room, “someone comes in and says I’m on 12 medications from four doctors, including the red one and the blue [pills],” says emergency-room physician John Halamka, who is chief information officer of Beth Israel Deaconess Medical Center in Boston and an advisor to Google Health. “If you gave me data that was structured and electronic, even if it was incomplete, that’s much better than I have now.”

Google Health already lets some users import medical data; so far, it has partnered with the Cleveland Clinic and Beth Israel Deaconess to give patients at both access to their electronic records. Meanwhile, pilot projects in which HealthVault users will be able to share information electronically with medical providers are in the planning stages at New York-Presbyterian Hospital and the Mayo Clinic. But “the exciting part of these systems isn’t just making data available to patients,” says Aurelia Boyer, chief information officer of New York-Presbyterian. It’s offering them tools to make use of the data on their own. “The ability to combine applications the way Facebook does is particularly exciting,” she says.